Class 8 Maths Worksheet: Algebraic Identities
The method (Split into easy parts): (a + b)² = a² + 2ab + b². (a − b)² = a² − 2ab + b². (a + b)(a − b) = a² − b²; so a² − b² = (a + b)(a − b). a² + b² = (a + b)² − 2ab = (a − b)² + 2ab.
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- 1.Use a² − b² = (a + b)(a − b) to find 83² − 64².
- 2.Use (a − b)² = a² − 2ab + b² to find 74².
- 3.Use a² − b² = (a + b)(a − b) to find 40² − 37².
- 4.Use (a − b)² = a² − 2ab + b² to find 96².
- 5.Find the value of x² + 2xy + y² when x = 13 and y = 11.
- 6.Use a² − b² = (a + b)(a − b) to find 79² − 72².
- 7.Use (a + b)² = a² + 2ab + b² to find 23².
- 8.Use (a + b)(a − b) = a² − b² to find 77 × 63.
- 9.Use (a + b)(a − b) = a² − b² to find 107 × 93.
- 10.Use (a − b)² = a² − 2ab + b² to find 53².
- 11.Find the value of x² + 2xy + y² when x = 12 and y = 4.
- 12.Use a² − b² = (a + b)(a − b) to find 21² − 8².
- 13.If a − b = 9 and ab = 10, what is a² + b²?
- 14.Use a² − b² = (a + b)(a − b) to find 76² − 4².
- 15.Find the value of x² + 2xy + y² when x = 4 and y = 2.
- 16.Use a² − b² = (a + b)(a − b) to find 26² − 4².
- 17.Use (a + b)² = a² + 2ab + b² to find 36².
- 18.Use a² − b² = (a + b)(a − b) to find 35² − 6².
- 19.Find the value of x² − 2xy + y² when x = 12 and y = 11.
- 20.If a + b = 3 and ab = 2, what is a² + b²?
- 21.Use (a − b)² = a² − 2ab + b² to find 83².
- 22.Use (a + b)² = a² + 2ab + b² to find 31².
- 23.Use (a + b)² = a² + 2ab + b² to find 63².
- 24.Find the value of x² + 2xy + y² when x = 12 and y = 2.
- 25.Use (a + b)² = a² + 2ab + b² to find 26².
- 26.Use (a − b)² = a² − 2ab + b² to find 28².
- 27.Use (a + b)(a − b) = a² − b² to find 41 × 39.
- 28.If a − b = 5 and ab = 6, what is a² + b²?
- 29.Use (a − b)² = a² − 2ab + b² to find 57².
- 30.If a + b = 9 and ab = 20, what is a² + b²?
- 31.If a + b = 21 and ab = 108, what is a² + b²?
- 32.Use a² − b² = (a + b)(a − b) to find 54² − 4².
- 33.Use (a + b)(a − b) = a² − b² to find 92 × 88.
- 34.Use (a + b)(a − b) = a² − b² to find 57 × 43.
- 35.If a + b = 10 and ab = 24, what is a² + b²?
- 36.Use (a + b)(a − b) = a² − b² to find 79 × 61.
- 37.If a + b = 12 and ab = 20, what is a² + b²?
- 38.If a − b = 2 and ab = 24, what is a² + b²?
- 39.Use (a − b)² = a² − 2ab + b² to find 32².
- 40.Find the value of x² − 2xy + y² when x = 10 and y = 8.
Answer key
- 2793
- 5476
- 231
- 9216
- 576
- 1057
- 529
- 4851
- 9951
- 2809
- 256
- 377
- 101
- 5760
- 36
- 660
- 1296
- 1189
- 1
- 5
- 6889
- 961
- 3969
- 196
- 676
- 784
- 1599
- 37
- 3249
- 41
- 225
- 2900
- 8096
- 2451
- 52
- 4819
- 104
- 52
- 1024
- 4
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